1. Field of the Invention
The present invention concerns a method for carrying out operations under water by means of a crane equipped with a tool which is erected on a pontoon which has been fixed and which can be jacked up.
In particular, the invention is related to the demolition of wrecks lying under water, for example on the bottom of the sea.
2. Discussion of the Related Art
The crane in this case has a tool such as a pair of shears or such at the end of its flexible arm with which pieces of the wreck can be loosened and pulled away.
As the wreck is situated under water, it is usually impossible for the crane attendant to see how he should operate said crane and especially the tool on the arm.
He may get his instructions from divers situated in the vicinity of the wreck and who can communicate with him.
In many cases, however, it is not possible for divers to follow and direct the operations of the crane, for example when there is a strong flow, at large depth or when there is not enough visibility. Moreover, divers can only stay under water for a relatively short time, so that this working method is relatively slow and expensive.